PKCS7 Encrypt using Multiple Certificates

Encrypts MIME using multiple digital certificates. Calls AddEncryptCert once per certificate, followed by a call to EncryptN. The MIME may be decrypted by any owner of one of the certificates + its associated private key.

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Dim mime As New Chilkat.Mime()

Dim success As Boolean
success = mime.UnlockComponent("Anything for 30-day trial.")
If (success = false) Then
    TextBox1.Text = TextBox1.Text & mime.LastErrorText & vbCrLf
    Exit Sub
End If


'  Build a simple MIME message to be encrypted:
mime.AddHeaderField("Content-Type","text/plain")
mime.AddHeaderField("abc","123")
mime.SetBody("This is a test")

'  A digital certificate is required to create PKCS7 encrypted MIME.
'  It can come from a variety of sources: .cer file, .pfx file, PEM files,
'  an in-memory representation, or directly from a Windows
'  registry-based certificate store.

'  Load one cert from a .cer file:
Dim cert1 As New Chilkat.Cert()
success = cert1.LoadFromFile("myCert.cer")
If (success = false) Then
    TextBox1.Text = TextBox1.Text & cert1.LastErrorText & vbCrLf
    Exit Sub
End If


'  Load another cert from the Windows registry store:
Dim cert2 As New Chilkat.Cert()
success = cert2.LoadByCommonName("Chilkat Sales")
If (success = false) Then
    TextBox1.Text = TextBox1.Text & cert2.LastErrorText & vbCrLf
    Exit Sub
End If


'  Tell the MIME object to use these certs for encrypting:
'  (AddEncryptCert shouldn't fail if we already know it contains
'  a valid certificate..)
success = mime.AddEncryptCert(cert1)
success = mime.AddEncryptCert(cert2)

'  Encrypt the MIME:
success = mime.EncryptN()
If (success = false) Then
    TextBox1.Text = TextBox1.Text & mime.LastErrorText & vbCrLf
    Exit Sub
End If


'  Display the MIME:
TextBox1.Text = TextBox1.Text & mime.GetMime() & vbCrLf

'  The resulting S/MIME looks something like this:
'  
abc: 123
Content-Disposition: attachment; filename="smime.p7m"
Content-Transfer-Encoding: base64
Content-Type: application/x-pkcs7-mime;
 name="smime.p7m"

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